感觉答案对为啥过不了

#include <stdio.h>
int main()
{
	int j, i, a[20020],n,sum,max;
	scanf("%d", &n);
		for (i = 0; i < n; i++)
			scanf("%d", &a[i]);
		max = a[0];
		for (i = 1; i < n; i++)
			if (max < a[i])
				max = a[i];
		for (i = 0; i < n; i++)
		{
			sum = 0;
			for (j = i; j < n; j++)
			{
				sum = a[j] + sum;
				if (max <= sum)
					max = sum;
			}
		}
	printf("%d", max);
	return 0;
}